Heterostructure Interface Construction of Cobalt/Nickel Diselenides Hybridized with sp2–sp3 Bonded Carbon to Boost Internal/External Sodium and Potassium Storage Dynamics

Abstract

Metal selenides exhibit great potential in energy storage systems owing to their diversified species, large interlayer spaces, and high theoretical specific capacity according to multiple ion-storage behaviors. In this work, heterostructured CoSe2/NiSe2 coupled with sp3 bonded N-doped carbon coating layers and interconnected with sp2 bonded carbon nanotubes is synthesized through a room-temperature wet-chemistry approach and a selenization route with Co–Ni Prussian blue analogues as the precursor. The hybrid exhibits enhanced energy storage properties when utilized as an anode material for sodium- and potassium-ion batteries. The excellent performance of the hybrid can be indexed to the delicately design of the CoSe2/NiSe2 heterostructure and the hybridization of it with sp2 and sp3 bonded carbonaceous materials synchronously. Experimental and theoretical calculation results demonstrate the heterostructure is constructed to acquire charge transfer driving forces to boost internal reaction dynamics. And there is a combination of the dual advantages of sp3 and sp2 bonded carbon, possessing not only the exceptional mechanics buffer capability of N-doped carbon coating layers but also the excellent electrical characteristics of carbon nanotubes to promote external reaction dynamics. In addition, to elucidate the differential sodium/potassium storage capability of the hybrid, theoretical calculations are further performed to indagate the adsorption energy of sodium and potassium on the CoSe2/NiSe2 heterointerface by establishing five Na/K adsorption sites. The research provides an effective strategy for the melioration of internal/external reaction dynamics to deliver ions durably and efficiently in energy storage regions.